Field of the Invention
The present invention relates to methods of treatment, prevention, management or amelioration of one or more symptoms of diseases or disorders associated with CD20 expression that encompass administration of a combination of: (A) one or more antibodies that specifically bind FcγRIIB, particularly human FcγRIIB, with greater affinity than said antibodies bind FcγRIIA, and (B) one or more antibodies that specifically bind to CD20. Such methods include methods of treating, preventing, managing or ameliorating one or more symptoms of a B cell related disease or disorder or an inflammatory disorder. The invention also provides pharmaceutical compositions comprising an anti-FcγRIIB antibody and an anti-CD20 antibody.
Description of Related Art
I. Fc Receptors and their Roles in the Immune System
The interaction of antibody-antigen complexes with cells of the immune system results in a wide array of responses, ranging from effector functions such as antibody-dependent cytotoxicity, mast cell degranulation, and phagocytosis to immunomodulatory signals such as regulating lymphocyte proliferation and antibody secretion. All these interactions are initiated through the binding of the Fc domain of antibodies or immune complexes to specialized cell surface receptors on hematopoietic cells. The diversity of cellular responses triggered by antibodies and immune complexes results from the structural heterogeneity of Fc receptors. Fc receptors share structurally related ligand binding domains which presumably mediate intracellular signaling.
The Fc receptors, members of the immunoglobulin gene superfamily of proteins, are surface glycoproteins that can bind the Fc portion of immunoglobulin molecules. Each member of the family recognizes immunoglobulins of one or more isotypes through a recognition domain on the a chain of the Fc receptor. Fc receptors are defined by their specificity for immunoglobulin subtypes. Fc receptors for IgG are referred to as FcγR, for IgE as FcεR, and for IgA as FcαR. Different accessory cells bear Fc receptors for antibodies of different isotype, and the isotype of the antibody determines which accessory cells will be engaged in a given response (reviewed by Ravetch J. V. et al. (1991) “Fc Receptors,” Annu. Rev. Immunol. 9: 457-92; Gerber et al. (2001) “Stimulatory And Inhibitory Signals Originating From The Macrophage Fcgamma Receptors,” Microbes and Infection, 3: 131-139; Billadeau et al. (2002), “ITAMs Versus ITIMs: Striking A Balance During Cell Regulation,” The Journal of Clinical Investigation, 2(109): 161-168; Ravetch J. V. et al. (2000) “Immune Inhibitory Receptors,” Science, 290: 84-89; Ravetch et al. (2001) “IgG Fc Receptors,” Annu. Rev. Immunol. 19:275-290; Ravetch (1994) “Fc Receptors: Rubor Redux,” Cell, 78(4): 553-560). The different Fc receptors, the cells that express them, and their isotype specificity is summarized in Table 1 (adapted from IMMUNOBIOLOGY: THE IMMUNE SYSTEM IN HEALTH AND DISEASE, 4th ed. 1999, Elsevier Science Ltd/Garland Publishing, New York).
A. Fcγ Receptors
Each member of this family is an integral membrane glycoprotein, possessing extracellular domains related to a C2-set of immunoglobulin-related domains, a single membrane spanning domain and an intracytoplasmic domain of variable length. There are three known FcγRs, designated FcγRI(CD64), FcγRII(CD32), and FcγRIII(CD16). The three receptors are encoded by distinct genes; however, the extensive homology between the three family members suggest they arose from a common progenitor perhaps by gene duplication. This invention specifically focuses on FcγRII(CD32).
B. FcγRII (CD32)
FcγRII proteins are 40 KDa integral membrane glycoproteins which bind only the complexed IgG due to a low affinity for monomeric Ig (106 M−1). This receptor is the most widely expressed FcγR, present on all hematopoietic cells, including monocytes, macrophages, B cells, NK cells, neutrophils, mast cells, and platelets. FcγRII has only two immunoglobulin-like regions in its immunoglobulin binding chain and hence a much lower affinity for IgG than FcγRI. There are three human FcγRII genes (FcγRII-A, FcγRII-B, FcγRII-C), all of which bind IgG in aggregates or immune complexes.
Distinct differences within the cytoplasmic domains of FcγRIIA (CD32A) and FcγRIIB (CD32B) create two functionally heterogenous responses to receptor ligation. The fundamental difference is that the A isoform initiates intracellular signaling leading to cell activation such as phagocytosis and respiratory burst, whereas the B isoform initiates inhibitory signals, e.g., inhibiting B cell activation.
C. Signaling Through FcγRs
Both activating and inhibitory signals are transduced through the FcγRs following ligation. These diametrically opposing functions result from structural differences among the different receptor isoforms. Two distinct domains within the cytoplasmic signaling domains of the receptor called immunoreceptor tyrosine based activation motifs (ITAMs) or immunoreceptor tyrosine based inhibitory motifs (ITIMS) account for the different responses. The recruitment of different cytoplasmic enzymes to these structures dictates the outcome of the FcγR-mediated cellular responses. ITAM-containing FcγR complexes include FcγRI, FcγRIIA, FcγRIIIA, whereas ITIM-containing complexes only include FcγRIIB.
Human neutrophils express the FcγRIIA gene. FcγRIIA clustering via immune complexes or specific antibody cross-linking serves to aggregate ITAMs along with receptor-associated kinases which facilitate ITAM phosphorylation. ITAM phosphorylation serves as a docking site for Syk kinase, activation of which results in activation of downstream substrates (e.g., PI3K). Cellular activation leads to release of proinflammatory mediators.
TABLE 1Receptors for the Fc Regions of Immunoglobulin IsotypesReceptorBindingCell TypeEffect of LigationFcγRIIgG1Macrophages, Neutrophils,Uptake Stimulation(CD64108 M−1Eosinophils, Dendritic cellsActivation ofrespiratory burstInduction of killingFcγRII-AIgG1Macrophages, Neutrophils,Uptake(CD32)2 × 106 M−1Eosinophils, Dendritic cells,GranulePlatelets, Langerhan cellsreleaseFcγRII-B2IgG1Macrophages, Neutrophils,Uptake Inhibition of(CD32)2 × 106 M−1EosinophilsStimulationFcγRII-BIIgG1B cells, Mast cellsNo uptake Inhibition(CD32)2 × 106 M−1of StimulationFcγRIIIIgG1NK cells, EosinophilInduction of Killing(CD16)5 × 105 M−1macrophages, Neutrophils,Mast CellsFcεRIIgG1Mast cells, EosinophilSecretion of1010 M−1BasophilsgranulesFcαRIIgG1, IgA2Macrophages, NeutropilsUptake Induction of(CD89)107 M−1EosinophilskillingII. Therapeutic Use of Anti-CD20 Antibodies
The interaction of antibody-antigen complexes with cells of the immune system results in a wide array of responses, ranging from effector functions such as antibody-dependent cytotoxicity, mast cell degranulation, and phagocytosis to immunomodulatory signals such as regulating lymphocyte proliferation The FcγRIIB gene is expressed on B lymphocytes; its extracellular domain is 96% identical to FcγRIIA and binds IgG complexes in an indistinguishable manner. The presence of an ITIM in the cytoplasmic domain of FcγRIIB defines this inhibitory subclass of FcγR. Recently the molecular basis of this inhibition was established. When colligated along with an activating FcγR, the ITIM in FcγRIIB becomes phosphorylated and attracts the SH2 domain of the inositol polyphosphate 5′-phosphatase (SHIP), which hydrolyzes phosphoinositol messengers released as a consequence of ITAM-containing FcγR-mediated tyrosine kinase activation, consequently preventing the influx of intracellular Ca++. Thus, crosslinking of FcγRIIB dampens the activating response to FcγR ligation and inhibits cellular responsiveness. B cell activation, B cell proliferation and antibody secretion is thus aborted.
T cells and B cells both comprise cell surface proteins which can be utilized as “markers” for differentiation and identification. One such human B cell marker is the human B lymphocyte-restricted differentiation antigen Bp35, referred to as “CD20.” CD20 is expressed during early pre-B cell development and remains until plasma cell differentiation. The CD20 molecule is a hydrophobic transmembrane protein with a molecular weight of approximately 35 kD located on pre-B and mature B lymphocytes (Valentine et al. (1989) “Phosphorylation of the CD20 Phosphoprotein In Resting B Lymphocytes. Regulation By Protein Kinase C,” J. Biol. Chem. 264:11282-11287; and Einfield et al. (1988) “Molecular Cloning Of The Human B cell CD20 Receptor Predicts A Hydrophobic Protein With Multiple Transmembrane Domains,” EMBO J. 7:711-717). CD20 is found on the surface of greater than 90% of B cells from peripheral blood or lymphoid organs and is expressed during early pre-B cell development and remains until plasma cell differentiation. CD20 is present on both normal B cells as well as malignant B cells. In particular, CD20 is expressed on greater than 90% of B cell non-Hodgkin's lymphomas (NHL) (Anderson et al. (1984) “Expression of Human B Cell-Associated Antigens On Leukemias And Lymphomas: A Model Of Human B Cell Differentiation,” Blood 63:1424-1433), but is not found on hematopoietic stem cells, pro-B cells, normal plasma cells, or other normal tissues (Tedder et al. (1985) “The B Cell Surface Molecule B1 Is Functionally Linked With B Cell Activation And Differentiation,” J. Immunol. 135:973-979). Specifically, the CD20 molecule may regulate a step in the activation process which is required for cell cycle initiation and differentiation and is usually expressed at very high levels on neoplastic (“tumor”) B cells. CD20, by definition, is present on both “normal” B cells as well as “malignant” B cells, i.e., those B cells whose unabated proliferation can lead to B cell lymphoma. Thus, the CD20 surface antigen has the potential of serving as a candidate for “targeting” of B cell lymphomas.
The use of antibodies to the CD20 antigen as diagnostic and/or therapeutic agents for B cell lymphoma has previously been reported. CD20 is a useful marker or target for B cell lymphomas as this antigen is expressed at very high densities on the surface of malignant B cells, i.e., B cells wherein unabated proliferation can lead to B cell lymphomas. The CD20 antigen is appealing for targeted therapy, because it does not shed, modulate, or internalize.
The United States Food and Drug Administration (FDA) has approved a chimeric CD20-specific monoclonal antibody (rituximab) for lymphoma therapy. Initial clinical experience with CD20-targeted immunotherapy suggests that malignant B cells may have a limited capacity to down regulate CD20 expression. These attributes make CD20 an attractive target for genetically engineered, redirected T cells.
III. Diseases of Relevance
A. Cancer
A neoplasm, or tumor, is a neoplastic mass resulting from abnormal uncontrolled cell growth which can be benign or malignant. Benign tumors generally remain localized. Malignant tumors are collectively termed cancers. The term “malignant” generally means that the tumor can invade and destroy neighboring body structures and spread to distant sites to cause death (for review, see Robbins and Angell, 1976, BASIC PATHOLOGY, 2d Ed., W.B. Saunders Co., Philadelphia, pp. 68-122). Cancer can arise in many sites of the body and behave differently depending upon its origin. Cancerous cells destroy the part of the body in which they originate and then spread to other part(s) of the body where they start new growth and cause more destruction.
More than 1.2 million Americans develop cancer each year. Cancer is the second leading case of death in the United States and if current trends continue, cancer is expected to be the leading cause of the death by the year 2010. Lung and prostate cancer are the top cancer killers for men in the United States. Lung and breast cancer are the top cancer killers for women in the United States. One in two men in the United States will be diagnosed with cancer at some time during his lifetime. One in three women in the United States will be diagnosed with cancer at some time during her lifetime. A cure for cancer has yet to be found. Current treatment options, such as surgery, chemotherapy and radiation treatment, are often times either ineffective or present serious side effects.
B. B Cell Malignancies
B cell malignancies, including, but not limited to, B cell lymphomas and leukemias, are neoplastic diseases with significant incidence in the United States. There are approximately 55,000 new lymphoma cases of per year in the U.S. (1998 data), with an estimated 25,000 deaths per year. This represents 4% of cancer incidence and 4% of all cancer-related deaths in the U.S. population. The revised European-American classification of lymphoid neoplasms (1994 REAL classification, modified 1999) grouped lymphomas based on their origin as either B cell lineage lymphoma, T cell lineage lymphoma, or Hodgkin's lymphoma. Lymphoma of the B cell lineage is the most common type of non-Hodgkin's lymphoma (NHL) diagnosed in the U.S. (Williams, HEMATOLOGY 6th ed. (Beutler et al. Ed.), McGraw Hill 2001). Chronic lymphocytic leukemia (CLL) is a neoplastic disease characterized by the accumulation of small, mature-appearing lymphocytes in the blood, marrow, and lymphoid tissues. CLL has an incidence of 2.7 cases per 100,000 in the U.S. The risk increases progressively with age, particularly in men. It accounts for 0.8% of all cancers and is the most common adult leukemia, responsible for 30% of all leukemias. In nearly all cases (>98%) the diseased cells belong to the B lymphocyte lineage. A non-leukemic variant, small lymphocytic lymphoma, constitutes 5-10% of all lymphomas, has histological, morphological and immunological features indistinguishable from that of involved lymph nodes in patients with B-CLL (Williams, 2001).
The natural history of chronic lymphocytic leukemia falls into several phases. In the early phase, chronic lymphocytic leukemia is an indolent disease, characterized by the accumulation of small, mature, functionally-incompetent malignant B cells having a lengthened life span. Eventually, the doubling time of the malignant B cells decreases and patients become increasingly symptomatic. While treatment with chemotherapeutic agents can provide symptomatic relief, the overall survival of the patients is only minimally extended. The late stages of chronic lymphocytic leukemia are characterized by significant anemia and/or thrombocytopenia. At this point, the median survival is less than two years (Foon et al. (1990) “Chronic Lymphocytic Leukemia: New Insights into Biology and Therapy,” Annals Int. Medicine 113:525-539). Due to the very low rate of cellular proliferation, chronic lymphocytic leukemia is resistant to treatment with chemotherapeutic agents.
C. Cancer Therapy
Currently, cancer therapy may involve surgery, chemotherapy, hormonal therapy and/or radiation treatment to eradicate neoplastic cells in a patient (See, for example, Stockdale, 1998, “Principles of Cancer Patient Management”, in SCIENTIFIC AMERICAN: MEDICINE, vol. 3, Rubenstein and Federman, eds., Chapter 12, Section IV). Recently, cancer therapy could also involve biological therapy or immunotherapy. All of these approaches pose significant drawbacks for the patient. Surgery, for example, may be contraindicated due to the health of the patient or may be unacceptable to the patient. Additionally, surgery may not completely remove the neoplastic tissue. Radiation therapy is only effective when the neoplastic tissue exhibits a higher sensitivity to radiation than normal tissue, and radiation therapy can also often elicit serious side effects. Hormonal therapy is rarely given as a single agent and although can be effective, is often used to prevent or delay recurrence of cancer after other treatments have removed the majority of the cancer cells. Biological therapies/immunotherapies are limited in number and may produce side effects such as rashes or swellings, flu-like symptoms, including fever, chills and fatigue, digestive tract problems or allergic reactions.
With respect to chemotherapy, there are a variety of chemotherapeutic agents available for treatment of cancer. A significant majority of cancer chemotherapeutics act by inhibiting DNA synthesis, either directly, or indirectly by inhibiting the biosynthesis of the deoxyribonucleotide triphosphate precursors, to prevent DNA replication and concomitant cell division (See, for example, Gilman et al., GOODMAN AND GILMAN'S: THE PHARMACOLOGICAL BASIS OF THERAPEUTICS, Eighth Ed. (Pergamom Press, New York, 1990)). These agents, which include alkylating agents, such as nitrosourea, anti-metabolites, such as methotrexate and hydroxyurea, and other agents, such as etoposides, camptothecins, bleomycin, doxorubicin, daunorubicin, etc., although not necessarily cell cycle specific, kill cells during S phase because of their effect on DNA replication. Other agents, specifically colchicine and the vinca alkaloids, such as vinblastine and vincristine, interfere with microtubule assembly resulting in mitotic arrest. Chemotherapy protocols generally involve administration of a combination of chemotherapeutic agents to increase the efficacy of treatment.
Despite the availability of a variety of chemotherapeutic agents, chemotherapy has many drawbacks (See, for example, Stockdale, 1998, “Principles of Cancer Patient Management”, in SCIENTIFIC AMERICAN: MEDICINE, vol. 3, Rubenstein and Federman, eds., Chapter 12, Section IV). Almost all chemotherapeutic agents are toxic, and chemotherapy causes significant, and often dangerous, side effects, including severe nausea, bone marrow depression, immunosuppression, etc. Additionally, even with administration of combinations of chemotherapeutic agents, many tumor cells are resistant or develop resistance to the chemotherapeutic agents. In fact, those cells resistant to the particular chemotherapeutic agents used in the treatment protocol often prove to be resistant to other drugs, even those agents that act by mechanisms different from the mechanisms of action of the drugs used in the specific treatment; this phenomenon is termed pleiotropic drug or multidrug resistance. Thus, because of drug resistance, many cancers prove refractory to standard chemotherapeutic treatment protocols.
B cell malignancy is generally treated with single agent chemotherapy, combination chemotherapy and/or radiation therapy. These treatments can reduce morbidity and/or improve survival, albeit they carry significant side effects. The response of B cell malignancies to various forms of treatment is mixed. For example, in cases in which adequate clinical staging of non-Hodgkin's lymphoma is possible, field radiation therapy can provide satisfactory treatment. Certain patients, however, fail to respond and disease recurrence with resistance to treatment ensues with time, particularly with the most aggressive variants of the disease. About one-half of the patients die from the disease (Devesa et al. (1987) “Cancer Incidence And Mortality Trends Among Whites In The United States, 1947-84,” J. Nat'l Cancer Inst. 79:701-770).
Though B cell lymphoma is generally responsive to chemotherapy or radiation therapy, these treatments carry significant side effects and do not work all the time. Moreover, a large percentage of patients remain at significant risk for disease relapse (Glass et al. (1997) “The National Cancer Data Base Report On Non-Hodgkin's Lymphoma,” Cancer 80:2311-2320). Investigational therapies for the treatment of refractory B cell neoplasia include autologous and allogeneic bone marrow or stem cell transplantation and gene therapies.
There is a significant need for alternative cancer treatments, particularly for treatment of cancer that has proved refractory to standard cancer treatments, such as surgery, radiation therapy, chemotherapy, and hormonal therapy. A promising alternative is immunotherapy, in which cancer cells are specifically targeted by cancer antigen-specific antibodies. Recently, immunotherapy using monoclonal antibodies to target B cell specific antigens has been introduced in the treatment of B cell neoplasia. The use of monoclonal antibodies to direct radionuclides, toxins, or other therapeutic agents offers the possibility that such agents can be delivered selectively to tumor sites, thus limiting toxicity to normal tissues.
Major efforts have been directed at harnessing the specificity of the immune response, for example, hybridoma technology has enabled the development of tumor selective monoclonal antibodies (See Green et al. (2000) “Monoclonal Antibody Therapy For Solid Tumors,” Cancer Treat Rev., 26: 269-286; Weiner L M (1999) “Monoclonal Antibody Therapy Of Cancer,” Semin Oncol. 26(suppl. 14):43-51), and in the past few years, the Food and Drug Administration has approved the first MAbs for cancer therapy: RITUXAN® (rituximab, anti-CD20) for non-Hodgkin's Lymphoma (NHL), CamPath® (alemtuzumab, anti-CD52) for B cell chronic lymphocytic leukemia (B-CLL) and Herceptin® [Trastuzumab, anti-(c-erb-2/HER-2)] for metastatic breast cancer (S. A. Eccles (2001) “Monoclonal Antibodies Targeting Cancer: ‘Magic Bullets’ Or Just The Trigger?” Breast Cancer Res., 3: 86-90). NHL and B-CLL are two of the most common forms of B cell neoplasia.
One of the most successful examples of immunotherapy using monoclonal antibodies to target B cell specific antigens is the use of a chimerized anti-CD20 monoclonal antibody, rituximab, in treating follicular lymphoma.
The chimeric anti-CD20 mAb, rituximab, is an effective treatment for low-grade or follicular B cell NHLs. However, not all NHL patients are amenable to treatment with currently available anti-CD20 antibodies, and rituximab has a response rate of about 50%. In phase I studies, rituximab induced a rapid depletion of CD20+ normal and lymphoma cells. Phase II trials with low-grade or follicular lymphoma showed a 50% response rate, whereas intermediate- to high-grade lymphomas showed a lower response rate. The reason for the heterogeneity of the response of different histologies and different patients is not clear. In addition to its anti-tumor effect, rituximab also induces rapid and profound depletion of CD20+ normal B cells in the peripheral blood and bone marrow. The depletion of normal B cells persisted long after the rituximab treatment, which can last for 6 months, followed by a slow recovery.
Use of these antibodies has some clinical efficacy, but not without side effects. The mechanism of how, e.g., rituximab kills the tumor cells in patients is not fully understood. Recent studies have suggested an important role for Antibody-Dependent Cellular Cytotoxicity (ADCC). The potency of antibody effector function, e.g., ADCC, is an obstacle to such treatment. Furthermore, with RITUXAN® and CamPath®, at least half the patients fail to respond and a fraction of responders may be refractory to subsequent treatments.
Thus, there is a need for alternative therapies with improved clinical efficacy for cancer, particularly, B cell malignancies, especially for patients that are refractory for standard cancer treatments and new immunotherapies such as RITUXAN®.
D. Inflammatory and Autoimmune Diseases
Inflammation is a process by which the body's white blood cells and chemicals protect our bodies from infection by foreign substances, such as bacteria and viruses. It is usually characterized by pain, swelling, warmth and redness of the affected area. Chemicals known as cytokines and prostaglandins control this process, and are released in an ordered and self-limiting cascade into the blood or affected tissues. This release of chemicals increases the blood flow to the area of injury or infection, and may result in the redness and warmth. Some of the chemicals cause a leak of fluid into the tissues, resulting in swelling. This protective process may stimulate nerves and cause pain. These changes, when occurring for a limited period in the relevant area, work to the benefit of the body.
In autoimmune and/or inflammatory disorders, the immune system triggers an inflammatory response when there are no foreign substances to fight and the body's normally protective immune system causes damage to its own tissues by mistakenly attacking self. There are many different autoimmune disorders which affect the body in different ways. For example, the brain is affected in individuals with multiple sclerosis, the gut is affected in individuals with Crohn's disease, and the synovium, bone and cartilage of various joints are affected in individuals with rheumatoid arthritis. As autoimmune disorders progress destruction of one or more types of body tissues, abnormal growth of an organ, or changes in organ function may result. The autoimmune disorder may affect only one organ or tissue type or may affect multiple organs and tissues. Organs and tissues commonly affected by autoimmune disorders include red blood cells, blood vessels, connective tissues, endocrine glands (e.g., the thyroid or pancreas), muscles, joints, and skin. Examples of autoimmune disorders include, but are not limited to, Hashimoto's thyroiditis, pernicious anemia, Addison's disease, type 1 diabetes, rheumatoid arthritis, systemic lupus erythematosus, dermatomyositis, Sjogren's syndrome, dermatomyositis, lupus erythematosus, multiple sclerosis, autoimmune inner ear disease myasthenia gravis, Reiter's syndrome, Graves disease, autoimmune hepatitis, familial adenomatous polyposis and ulcerative colitis.
Rheumatoid arthritis (RA) and juvenile rheumatoid arthritis are types of inflammatory arthritis. Arthritis is a general term that describes inflammation in joints. Some, but not all, types of arthritis are the result of misdirected inflammation. Besides rheumatoid arthritis, other types of arthritis associated with inflammation include the following: psoriatic arthritis, Reiter's syndrome, ankylosing spondylitis arthritis, and gouty arthritis. Rheumatoid arthritis is a type of chronic arthritis that occurs in joints on both sides of the body (such as both hands, wrists or knees). This symmetry helps distinguish rheumatoid arthritis from other types of arthritis. In addition to affecting the joints, rheumatoid arthritis may occasionally affect the skin, eyes, lungs, heart, blood or nerves.
Rheumatoid arthritis affects about 1% of the world's population and is potentially disabling. There are approximately 2.9 million incidences of rheumatoid arthritis in the United States. Two to three times more women are affected than men. The typical age that rheumatoid arthritis occurs is between 25 and 50. Juvenile rheumatoid arthritis affects 71,000 young Americans (aged eighteen and under), affecting six times as many girls as boys.
Rheumatoid arthritis is an autoimmune disorder where the body's immune system improperly identifies the synovial membranes that secrete the lubricating fluid in the joints as foreign. Inflammation results, and the cartilage and tissues in and around the joints are damaged or destroyed. In severe cases, this inflammation extends to other joint tissues and surrounding cartilage, where it may erode or destroy bone and cartilage and lead to joint deformities. The body replaces damaged tissue with scar tissue, causing the normal spaces within the joints to become narrow and the bones to fuse together. Rheumatoid arthritis creates stiffness, swelling, fatigue, anemia, weight loss, fever, and often, crippling pain. Some common symptoms of rheumatoid arthritis include joint stiffness upon awakening that lasts an hour or longer; swelling in a specific finger or wrist joints; swelling in the soft tissue around the joints; and swelling on both sides of the joint. Swelling can occur with or without pain, and can worsen progressively or remain the same for years before progressing.
The diagnosis of rheumatoid arthritis is based on a combination of factors, including: the specific location and symmetry of painful joints, the presence of joint stiffness in the morning, the presence of bumps and nodules under the skin (rheumatoid nodules), results of X-ray tests that suggest rheumatoid arthritis, and/or positive results of a blood test called the rheumatoid factor. Many, but not all, people with rheumatoid arthritis have the rheumatoid-factor antibody in their blood. The rheumatoid factor may be present in people who do not have rheumatoid arthritis. Other diseases can also cause the rheumatoid factor to be produced in the blood. That is why the diagnosis of rheumatoid arthritis is based on a combination of several factors and not just the presence of the rheumatoid factor in the blood.
The typical course of the disease is one of persistent but fluctuating joint symptoms, and after about 10 years, 90% of sufferers will show structural damage to bone and cartilage. A small percentage will have a short illness that clears up completely, and another small percentage will have very severe disease with many joint deformities, and occasionally other manifestations of the disease. The inflammatory process causes erosion or destruction of bone and cartilage in the joints. In rheumatoid arthritis, there is an autoimmune cycle of persistent antigen presentation, T cell stimulation, cytokine secretion, synovial cell activation, and joint destruction. The disease has a major impact on both the individual and society, causing significant pain, impaired function and disability, as well as costing millions of dollars in healthcare expenses and lost wages. (See, for example, the NIH website and the NIAID website).
Currently available therapy for arthritis focuses on reducing inflammation of the joints with anti-inflammatory or immunosuppressive medications. The first line of treatment of any arthritis is usually anti-inflammatories, such as aspirin, ibuprofen and Cox-2 inhibitors such as celecoxib and rofecoxib. “Second line drugs” include gold, methotrexate and steroids. Although these are well-established treatments for arthritis, very few patients remit on these lines of treatment alone. Recent advances in the understanding of the pathogenesis of rheumatoid arthritis have led to the use of methotrexate in combination with antibodies to cytokines or recombinant soluble receptors. For example, recombinant soluble receptors for tumor necrosis factor (TNF)-α have been used in combination with methotrexate in the treatment of arthritis. However, only about 50% of the patients treated with a combination of methotrexate and anti-TNF-α agents such as recombinant soluble receptors for TNF-α show clinically significant improvement. Many patients remain refractory despite treatment. Difficult treatment issues still remain for patients with rheumatoid arthritis. Many current treatments have a high incidence of side effects or cannot completely prevent disease progression. So far, no treatment is ideal, and there is no cure. Novel therapeutics are needed that more effectively treat rheumatoid arthritis and other autoimmune disorders.